Assessment of mitigation measures to reduce interactions between sea turtles and longline fishery

Citation
Kiyota M, Yokota K, Nobetsu T, et al (2000) Assessment of mitigation measures to reduce interactions between sea turtles and longline fishery. In: Proceedings of the 5th Workshop on SEASTER. pp p24–29
Abstract

Sea turtles have been receiving negative impacts from both human activities and natural factors. Interactions with commercial fisheries are one of the anthropogenic factors affecting sea turtle populations. A variety of mitigation measures have been developed and tested to reduce incidental mortality of sea turtles in longline fishery. We review potential technical measures to alleviate longline-sea turtle interactions and show some preliminary results from our field and laboratory experiments. Fishing gear modifications aim at reducing hooking rates of sea turtles by changing fishing hooks and baits or by the use of additional devices. Results of our field experiments showed that the use of circle hooks altered hooking position and reduced deep hooking of sea turtles. Fish baits showed lower catch rates of sea turtles than squid baits, because sea turtles were more likely to swallow the whole squid bait due to tough and flexible muscle texture of squids. Fishing practice modifications aim at avoiding the overlap between fishing operations and sea turtles either spatially or temporally. In the oceanic area, sea turtles spend most of their time within the shallow surface layer (